Reverse-phase chromatography, aqueous gel exclusion, and nonaqueous gel exclusion were assessed as procedures for preparative fractionation of the tumor-localizing product hematoporphyrin derivative. Porphyrin accumulation, fluorescence, and photodynamic cytotoxicity were monitored using the murine Sarcoma 180 tumor. Aqueous gel exclusion chromatography can provide a hematoporphyrin derivative fraction enriched in the tumor-localizing component. A further enrichment occurs when this procedure is carried out at 55°C, but nonlocalizing porphyrins could not be eliminated. While providing a better separation, reverse-phase chromatography cannot provide a tumor-localizing fraction free from contaminating protoporphyrin. However, this and other contaminants can be eliminated from the tumor-localizing fraction via nonaqueous gel exclusion chromatography. This latter separation provides two tumor-localizing products: (a) a fast-eluting fraction enriched in the major photosensitizing component(s); and (b) a more complex slowly eluting fraction enriched in fluorescence localizers.
Supported by Grant CA 23378 from the National Cancer Institute, NIH, Department of Health and Human Services.